Usually trucks are built with the largest possible cargo space. This generally means that the end surface is large, being in direct proportional relation to the air resistance, and hence the fuel consumption is high. On the other hand, the available cargo space is seldom utilized completely in practice, since oftentimes small freight units are transported or a free space is left on top of the cargo to provide sufficient freedom of movement when loading or unloading.
Accordingly, the problem on which the invention is based was to provide a system that minimizes the end surface of the truck and thus the fuel consumption in dependence on the cargo space actually utilized.